The Principles of Clinical Cytogenetics - Extra Materials - Springer

Basic Laboratory Procedures 79
Once the appropriate number of mitotic cells has been examined and analyzed, a representative
sample must be selected for imaging and ultimate preparation of karyotypes. This will involve either
traditional photography and manual arrangement of chromosomes (becoming increasingly rare) or computerized
image capture and automated karyotyping (see Chapter 7). Many laboratories also image
additional cells, to be included as references in the patient chart. Ultimately, summary information
(patient karyotype, banding resolution, number of cells examined, analyzed and imaged, etc.) is recorded
in the patient’s file and is used, either manually or via computer, in the clinical report.
The final steps of the process typically involve a clerical review of all relevant clinical, technical,
and clerical data, examination of the patient’s chart and karyotypes by the laboratory director (often
preceded by the supervisor and/or other senior laboratory personnel), and generation of the formal
clinical report. In addition to the appropriate physician and patient demographic information, this
should include the number of metaphases that were examined microscopically, the banding resolution
obtained for the specimen, the number of cells analyzed in detail, the number of karyotypes
prepared, the patient’s karyotype, and a clinical interpretation of the results, including, where appropriate,
recommendations for additional testing and/or genetic counseling.
SUMMARY
The purpose of this chapter is to provide a general overview of the many steps involved from receipt
of a sample in the cytogenetics laboratory to the generation of a patient report and to impress upon the
reader the labor-intensive nature of this work. Although the basic procedure is always the same, there
are culturing and processing variations that are sample type dependent, choices of methodology that
are diagnosis dependent, and microscopic analysis decisions that are results dependent. All of these, in
turn, depend on individuals with the appropriate expertise and dedication to patient care.
REFERENCES
Because of the nature of this chapter, individual citations were not practical. In addition to the
authors’ personal experience, the following were used as supplemental sources of information:
• Barch, M.J., Knutsen, T. and Spurbeck, J.L. (eds.) (1997) The AGT Cytogenetic Laboratory
Manual. Raven–Lippincott, Philadelphia.
• Rooney, D.E. (ed.) (2001) Human Cytogenetics: Constitutional Analysis, 3rd ed. Oxford University
Press, Oxford.
• Rooney, D.E. and Czepulkowski, B.H. (eds.) (1992) Human Cytogenetics: A Practical Approach,
Volume I: Constitutional Analysis. IRL/Oxford University Press, New York.
• Verma, R.S. and Babu, A. (1995) Human Chromosomes. McGraw-Hill, New York.